Residue monitoring system for an agricultural harvester and agricultural harvester

ABSTRACT

A monitoring system for a combine harvester. The monitoring system includes a sensor configured to provide a measurement wave to a flow of crop residue on the harvester and to receive a response wave from the flow of crop residue. The monitoring system further includes a processor having an input terminal for receiving a response signal of the sensor representative of the response wave. The processor is configured to determine a crop parameter associated with the density of the flow of crop based on the response signal of the sensor. The processor further has an output terminal for outputting a density signal representing the crop parameter.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 15/247,462,entitled “MONITORING SYSTEM FOR AN AGRICULTURAL HARVESTER ANDAGRICULTURAL HARVESTER”, filed Aug. 25, 2016, which is incorporatedherein by reference.

FIELD OF THE INVENTION

The invention relates to the field of agricultural harvesters such ascombines which including a threshing assembly for separating the variouscomponents of a harvested crop, e.g. grain and straw.

In particular, the invention relates to a monitoring system forassessing the quality of straw.

BACKGROUND OF THE INVENTION

An agricultural harvester, also referred to as a combine or combineharvester because it typically combines multiple harvesting functions,typically includes a header for removing a crop from a field and aso-called threshing tool for performing a threshing operation on thecrop in order to separate the grain from the non-grain material such asstraw. Typically, the straw is outputted by the harvester in such mannerthat it can be easily gathered into bales.

Because straw bales represent an important economic value, it isimportant to ensure that the process of gathering the straw is asefficient as possible, i.e. it is important to ensure that substantiallyall the straw that is outputted by the combine is gathered into bales.At present, the operator of the combine needs to check the quality ofthe straw as outputted manually and, based on its findings, adjustoperational parameters of the threshing and separation tool. In order tomaintain a desired quality of the straw, such a check should be doneregularly at sufficiently small intervals to accommodate for varyingcrop conditions. This may however be rather time-consuming, resulting inan increased period of time for performing the harvesting process.

As such, there is a need to provide in an alternative way of assessingthe quality of straw that is outputted by a combine.

SUMMARY OF THE INVENTION

It would be desirable to provide in an agricultural harvester whichenables an assessment of the quality of straw in a more efficientmanner. Therefore, the present invention provides, in an embodiment, ina monitoring system for a combine harvester, the monitoring systemcomprising:

a sensor configured to provide a measurement wave to a flow of cropresidue on the harvester and to receive a response wave from the flow ofcrop residue;

a processor having an input terminal for receiving a response signal ofthe sensor representative of the response wave; the processor beingconfigured to determine a crop parameter associated with the density ofthe flow of crop based on the response signal of the sensor;

the processor further comprising an output terminal for outputting adensity signal representing the crop parameter.

The monitoring system according to the present invention, which may e.g.be mounted to a combine harvester for monitoring a flow of crop residuesuch as straw, enables to generate a signal, referred to as a densitysignal, representative of a crop parameter that can be associated withthe density of the flow of crop residue. As an example, the cropparameter may e.g. be a height or thickness of the flow of crop residue,e.g. monitored as the crop residue progresses on the straw hood of theharvester, i.e. before being on the field.

In accordance with the present invention, the sensor is configured toprovide a measurement wave to a flow of crop residue. Such a measurementwave may e.g. be an acoustic pulse, an ultrasonic pulse or anelectromagnetic pulse or wave. In an embodiment, the sensor may e.g.include a transmitter configured to transmit the measurement wave, e.g.an acoustic or ultrasonic wave, to the flow of crop residue and areceiver configured to receive a response wave from the flow of cropresidue.

In accordance with the present invention, the sensor may be applied inso-called reflective mode or transmissive mode. In the latter case, theresponse wave from the flow of crop material is the signal that remainsafter having passed through the flow of crop residue. In this case, thesensor may include a transmitter and a receiver that are arranged onopposite sides of the flow of crop residue. In the former case, theresponse wave may be a signal that is reflected off of the flow of cropresidue. In this case, a transmitter and receiver of the sensor may bearranged on the same side of the flow of crop residue, e.g. adjacent toeach other.

The monitoring system according to the present invention is configuredto provide the measurement wave to the flow or crop residue, while thecrop residue is on the harvester, e.g. being processed. This enables toprovide in a more controlled monitoring of the crop residue parametersor quality compared to arrangements that sense a property of the cropresidue when the crop residue is already outputted by the harvester andon the field. When the crop residue, e.g. straw in case of theharvesting of grain, is already outputted onto the field, an assessmentof the density of the crop residue is more difficult and may e.g.required additional measurements such as ground level measurements orheight or thickness measurements of the layer of crop residue on thefield.

In an embodiment, the monitoring system is mounted to a combineharvester according to the present invention. In general, such aharvester comprises a header for harvesting a crop of a field, athreshing system for separating a crop residue from the harvested crop,and a monitoring system according to the invention. As an example, theharvester may be configured to harvest grain whereby the threshingsystem is configured to separate the grain and the straw, the straw thusbeing considered the crop residue. The use of the monitoring systemaccording to the present invention on such a combine harvester enablesto monitor the straw density prior to the straw being outputted onto thefield, i.e. while the straw is still on the harvester, e.g. beingprocessed or transported. As an example, the monitoring system may beconfigured to monitor the flow of straw while being transported on aso-called straw hood of the harvester. Such a straw hood may e.g.comprise a ramp that is mounted at a rear end of the harvester forguiding the flow of crop residue towards the field. The ramp may e.g. bea metal plate or the like.

In such embodiment, the sensor of the monitoring system may e.g. bemounted above the ramp such that the flow of crop residue passes inbetween the sensor and the ramp.

In an embodiment, the density signal is provided to an input terminal ofa control unit of the harvester, the control unit being configured tocontrol an operating parameter of the threshing system. In suchembodiment, the control unit may further comprise a processor forprocessing the density signal and determining a control signal for thethreshing system, in particular for controlling a component of thethreshing system.

In general, it would be desirable to have the density of the layer ofstraw (also referred to as the swath) as low as possible, thusfacilitating a subsequent pick-up of the straw for baling.

These and other aspects of the invention will be more readilyappreciated as the same becomes better understood by reference to thefollowing detailed description and considered in connection with theaccompanying drawings in which like reference symbols designate likeparts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a monitoring system mounted to a combine harvesteraccording to an embodiment of the present invention;

FIG. 2a depicts a monitoring system according to an embodiment of thepresent invention.

FIG. 2b depicts an applied pulse and response pulses using a monitoringsystem according to the present invention.

FIG. 3 depicts a threshing and separation system as can be applied in acombine harvester according to the present invention;

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 depicts, in a cross-sectional view, a combine harvester 1including a monitoring system 10 according to an embodiment of thepresent invention.

The agricultural harvester 1 can e.g. be configured to harvest grain asa crop, whereby straw can be considered a crop residue. In the harvesteraccording to the present invention, this crop residue is monitored by amonitoring system configured to determine a signal that can beassociated with the density of the crop residue, further on alsoreferred to as a density signal. In the embodiment as shown, themonitoring system comprises a sensor 10.1. In case of the harvesting ofgrain, the crop residue, i.e. the straw may either be processed furtherand chopped into comparatively small parts that are left on the field,or it may be outputted onto the field and subsequently gathered intobales. In the latter case, it may be advantageous to ensure that thedensity of the straw as outputted onto the field is as low as possible,thereby facilitating the picking up of the straw. Without a monitoringsystem, the quality of the straw, i.e. reflected by the density, wouldhave to be checked manually by the operator of the harvester. In suchcase, this check would have to be repeated regularly, in order to takevarying harvesting conditions into account. Such a repeated check mayhowever be time-consuming and adversely affects the harvesting timerequired. By substantially continuously monitoring the density of thestraw, e.g. using a monitoring system according to the presentinvention, a more effective subsequent baling of the straw can berealized.

Further, the monitoring system according to the present invention isconfigured to monitor the flow of crop residue while on the harvester.This provides in a more controlled environment to monitor the cropresidue compared to the use of monitoring system that monitors the swathof straw on the field. In the latter case, estimating the density of theswath may be cumbersome and may involve determine the height of theswath and a ground level.

By sensing the crop residue on the harvester, rather than on the field,a more accurate determination of the density may be obtained. Inaddition, in case the density signal is applied in a control loop of thethreshing system of the harvester (see further on), a faster responsemay be realized compared to a sensing of the crop residue density on thefield.

The agricultural harvester 1 as schematically shown in FIG. 1 furthercomprises a header 3 or harvesting mechanism for cutting a crop on afield. The cup crop is subsequently transported, e.g. by way of one ormore augers or one or more conveyers to a threshing mechanism orthreshing system 2 configured to separate the cut crop into a firststream or flow (indicated by the arrow 11), substantially composed ofgrain and chaff, and a second stream or flow (indicated by the arrow12), referred to as the crop residue, substantially composed of straw.

In an embodiment, as shown in more detail in FIG. 3, the threshingsystem 2 is of an axial flow type including a rotor that is at leastpartially enclosed by and rotatable within a corresponding perforatedconcave. The cut crop that enters the threshing system 2 (indicated byarrow 13) is threshed and separated by the rotation of the rotor withinthe perforated concave, thereby providing the separation into the firststream or flow (through the perforations of the perforated concave) andthe second stream that exits the threshing system in axial direction.The first stream 11 may e.g. be conveyed via a grain pan to a cleaningmechanism 4, e.g. including one or more sieves 5, 6, driven by a driveassembly 8. The fine material, e.g. grain, that is collected below thesieves is transported by way of an auger 7, e.g. to an elevator. Thesecond stream 12 is conveyed to an outlet of the harvester, e.g.comprising a straw hood 15. In the embodiment as shown, the straw hood15 comprises a ramp 15.1 via which the flow of crop residue, e.g. straw,can be outputted onto the field.

In the embodiment as shown, the harvester further includes a monitoringsystem including a sensor 10.1, the sensor being configured to provide ameasurement wave to the flow of crop residue on the harvester, inparticular on the ramp 15.1, and to receive a response wave from theflow of crop residue. In order to realize this, the sensor 10.1 is, inthe embodiment as shown, mounted substantially above the ramp 15.1. Inthe arrangement as shown, the sensor may e.g. include a transmitter fortransmitting an ultrasonic signal, e.g. an ultrasonic pulse towards theramp 15.1. In case there is no straw being outputted, a return pulsewill be received, e.g. by a receiver of the sensor 15.1 at a particularinstance, depending on the distance between the sensor and the ramp. Incase straw is present on the ramp (see FIG. 2a ), a multiple returnpulses may be received.

FIG. 2a schematically shows in more detail an embodiment of themonitoring system 10 according to the present invention.

FIG. 2a schematically shows a flow (indicated by the arrow 200) of strawthat is outputted onto a field via a ramp 15.1 of a straw hood of acombine harvester. FIG. 2a further shows a monitoring system 10configured to monitor the flow of crop residue 200 on the harvester,i.e. on the ramp 15.1 of the harvester. The monitoring system 10 asshown comprises a sensor 10.1 configured to send a measurement wave 210to the flow of crop residue 200 on the ramp 15.1. in the embodiment asshown, the wave 210 may be an ultrasonic pulse that is projected towardsthe ramp 15.1. Due to the presence of the flow of crop residue, theultrasonic pulse can be reflected at various positions on and in thelayer of crop residue, resulting in multiple reflections that may bereceived by a receiver of the sensor 10.1.

In an embodiment, the sensor 10.1 may thus comprises a transmitter fortransmitting a signal such as an ultrasonic pulse 210 to the flow ofcrop residue on the harvester and a receiver for receiving a returnsignal. In such embodiment, the transmitter and receiver may be arrangedadjacent to each or may be somewhat separated from each other. As willbe understood by the skilled person, the angle at which the pulse 210impacts the ramp 15.1 may affect the direction of the reflected pulse orpulses and may thus have an effect on the appropriate or most effectivelocation for positioning the receiver of the sensor. In an embodiment,the sensor is configured to send the pulse to the straw hood, i.e. tothe ramp 15.1 of the straw hood in a direction substantiallyperpendicular to a plane of the straw hood. In such embodiment, it maybe advantageous to locate the receiver close to the transmitter.

In an embodiment, the functionality of a transmitter and a receiver maybe combined in a so-called transceiver which may both be configured totransmit a pulse and pick or receive any reflected pulses in response tothe transmitted pulse.

FIG. 2b schematically depicts an intensity level Int of a transmittedpulse T and a subsequent response comprising reflected pulses A, B, andC, in FIG. 2a , the locations A, B, and C are used to indicate thepositions from which the respective reflected pulses originate.

Depending on the size and structure of the flow of crop residue, e.g.straw, multiple reflected pulses may be observed, e.g. by a receiver ofthe sensor 10.1. Since reflected pulse A is the first pulse to bereceived by the receiver, one can assume the location from whichreflected pulse A originates to be the closest to the receiver of thesensor. As such, reflected pulse A can be assumed to originate from thetop surface of the layer of crop residue, as indicated in FIG. 2a . Ascan be seen in the intensity level graph of FIG. 2b , reflected pulse Cis the last pulse to be received by the receiver. As such, it can beassumed that this pulse represents a reflection on the straw hooditself, i.e. on a surface of the ramp 15.1 of the straw hood.

As such, the time or period t_dens indicated in FIG. 2b , i.e. betweenthe receipt of the first reflected pulse A and the last reflected pulseC can be considered a value that is proportional to the thickness of theflow of crop residue 200, the thickness of the layer being indicated byreference number 220 in FIG. 2a . Further, one or more intermediatereflected pulses, such as pulse B may be present as well.

In accordance with the present invention, the monitoring system 10further comprises a processing unit 230 having an input terminal 240 toreceive a response signal 245 of the sensor 10.1 representative of theresponse wave, e.g. the reflected pulses as shown in FIG. 2b . Such aprocessing unit can be embodied as a processor, a microprocessor, acomputer or the like and in general comprises a memory unit for storingdata such as the response signal and a computational unit for processingthe data. In accordance with the present invention, the processor 230 isconfigured to determine a crop parameter associated with the density ofthe flow of crop based on the response signal of the sensor. In theexample given in FIG. 2a , the height or thickness 220 of the flow ofcrop residue can be considered such a crop parameter. As indicated, thisparameter may be derived based on the assessment of the timing of thereceived pulse or pulses. In accordance with the present invention, theprocessor 230 further comprises an output terminal 250 for outputting adensity signal 255 representing the crop parameter. Such a densitysignal 255 may e.g. be provided to a control unit of to combineharvester to which the monitoring system is mounted, e.g. to control athreshing system of the harvester.

With respect to the sensor arrangement as schematically shown in FIG. 2a, it can be noted that the arrangement of transmitter and receiver asdisplayed operates in a reflective mode; i.e. the receiver of the sensorbeing arranged to receive a reflected pulse or pulses. It should howeverbe noted that sensor arrangements that operate in a transmissive modecan be considered as well. In such arrangement, the receiver may e.g. bemounted in such manner that the flow of crop residue is between thetransmitter and the receiver. Referring to FIG. 2a , such an arrangementmay be obtained by mounting the receiver onto the ramp 15.1.

In such embodiment, the intensity of the wave as received by thereceiver compared to the wave that was emitted by the transmitter, canbe considered an indication of the density of the crop residue. Morespecifically, in case the density of the crop residue is comparativelylow, the intensity of the wave as received by the receiver on the ramp15.1 may be comparatively high and vice versa.

In an embodiment, the monitoring system according to the presentinvention provides in a more detailed density signal, by takingadditional parameters into account.

In an embodiment, the processing system may be configured to receive, asan input, a value of the width of the flow of crop residue, e.g.corresponding to the width of the straw hood or ramp 15.1 of the strawhood. Note that a value of the width may e.g. be derived from anoperating parameter or setting of the straw hood or may be derived froma measurement. In particular, a similar measurement as described withrespect to determining the height of the flow of crop residue may beapplied to determine the width of the flow of crop residue.

In an embodiment, the monitoring system is further provided with avelocity sensor configured to provide a velocity signal representativeof the velocity of the flow of crop residue. Such a velocity sensor maye.g. be an image based sensor configured to capture one or more imagesof the crop residue passing at a particular position and provide theimages to the processing unit of the monitoring system. Using patternrecognition (or pixel flow or other image processing techniques likecross-correlation of 2 or more images obtained after each other in time. . . ), the processing unit may process the images to derive a velocityof the flow of crop residue.

Combined with information on the height and the width of the flow ofcrop residue, the velocity signal enables the processing unit to derivean estimate of the volume of crop residue that is outputted per unit oftime.

In an embodiment, the monitoring system may further include a sensor forassessing the infeed of the harvester, i.e. the amount of crop that isbeing harvested, i.e. taken in by the header of the harvester. Suchsensors may e.g. be image based sensors or laser based sensors or evenradar based sensors. Based on input signals from such sensors, theprocessing unit of the monitoring system according to the presentinvention may e.g. determine or estimate the weight of crop residue thatis processed per unit of time. Combined with volume of crop residue thatis outputted per unit of time, the density of the crop residue may e.g.be determined or estimated.

In an embodiment, as explained in more detail below, the density signalas determined by the monitoring system according to the presentinvention may be applied in a combine harvester according to the presentinvention to control an operating parameter of the threshing system ofthe harvester. In such embodiment, the harvester may e.g. comprise acontrol unit for controlling an operating parameter of the threshingsystem, the control unit comprising:

an input terminal for receiving the density signal;

a processor for processing the density signal and determining a controlsignal for the threshing system based on the density signal; and

an output terminal for outputting the control signal to the threshingsystem to control the operating parameter.

In an embodiment, the functionality of the processing unit of themonitoring system and the control unit of the harvester may be combinedand integrated in a single control unit or controller.

FIG. 3 schematically shows an example of a threshing system 24 as can beapplied in a harvester according to the present invention. The threshingsystem 24 as shown includes a rotor 40 that is at least partlysurrounded by a perforated concave 42. By the rotation of the rotor 40,the cut or harvested crop 300 is threshed and separated into a flow oflarger elements 310 such as stalks or straw and a flow of smallerelements 320 including grain 72 and smaller non-grain material such aschaff and dust. The latter flow may e.g. be processed by a cleaningsystem 26 that includes sieves a grain pan 44 and sieves 46 and 48.

In accordance with an embodiment of the present invention, the operationof the threshing system 24 can be controlled by a control unit 330having an input terminal 340 and an output terminal 350, the inputterminal being configured to receive the density signal 345, e.g.density signal 245 as shown in FIG. 2a , from the processing unit of themonitoring system.

The control unit 330 is configured to determine, based on the densitysignal, a control signal 355 (outputted via the output terminal 350) forcontrolling an operation of the threshing system 24. As an example,based on the density signal, the control unit may e.g. determine thatthe velocity of the rotor 40 should be adjusted or that a spacingbetween the rotor 40 and the perforated concave 42 should be adjusted,in order to obtain a more preferred density of the flow 320 of cropresidue, i.e. a reduced density.

In an embodiment, the density signal as applied to the control unit 330may be obtained by processing any of the further parameters ormeasurements as described above, i.e. the width of the flow of cropdensity or the velocity of the flow of crop density or a signalrepresenting the infeed or intake of the harvester.

In an embodiment, the control unit may further be configured to receive,as an input signal, a power signal representative of the powerconsumption of the threshing system. It has been observed that the powerconsumption of the threshing system can be an indication of the size oraverage size of the flow or straw, i.e. crop residue, that is outputtedby the threshing system. Further, the smaller the size or average sizeof the crop residue, the higher the density of the crop residue. Assuch, a signal representing the power consumption of the threshingsystem may be applied, by the control unit, as an indication of thestraw quality, in particular the straw density. As such, in anembodiment of the present invention, the control unit of the combineharvester may be configured to determine a control signal forcontrolling an operation or operational parameter of the threshingsystem based on both the density signal as received from the monitoringsystem and the power signal (e.g. obtained from a power sensorassociated with the threshing system).

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which can be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure. Further, the terms and phrases usedherein are not intended to be limiting, but rather, to provide anunderstandable description of the invention.

The terms “a” or “an”, as used herein, are defined as one or more thanone. The term plurality, as used herein, is defined as two or more thantwo. The term another, as used herein, is defined as at least a secondor more. The terms including and/or having, as used herein, are definedas comprising (i.e., open language, not excluding other elements orsteps). Any reference signs in the claims should not be construed aslimiting the scope of the claims or the invention.

The mere fact that certain measures are recited in mutually differentdependent claims does not indicate that a combination of these measurescannot be used to advantage.

The term coupled, as used herein, is defined as connected, although notnecessarily directly, and not necessarily mechanically.

A single processor or control unit may fulfil the functions of severalitems recited in the claims.

The invention claimed is:
 1. A monitoring system for a combine harvestercomprising a straw hood with a ramp, the monitoring system comprising: asensor configured to provide a measurement wave to a flow of cropresidue as the crop residue progresses on the ramp of the straw hood andto receive a response wave from the flow of crop residue as the cropresidue progresses on the ramp of the straw hood; and a processor havingan input terminal for receiving a response signal of the sensorrepresentative of the response wave, the processor configured todetermine a crop parameter associated with a density of the flow of cropresidue based on the response signal of the sensor, the processorfurther comprising an output terminal for outputting a density signalbased on the crop parameter.
 2. The monitoring system according to claim1, wherein the response wave originates from at least one of a topsurface of the flow of crop residue on the ramp of the straw hood and asurface of the ramp of the straw hood.
 3. The monitoring systemaccording to claim 1, wherein the sensor is an ultrasonic sensorcomprising a transmitter configured to transmit the measurement wave tothe flow of crop residue and a receiver configured to receive theresponse wave from the flow of crop residue.
 4. The monitoring systemaccording to claim 3, wherein the transmitter is configured to output anultrasonic pulse as the measurement wave, the receiver being configuredto receive, as the response wave, a response of the ultrasonic pulseafter impacting the flow of crop residue.
 5. The monitoring systemaccording to claim 3, wherein the transmitter and receiver areconfigured in a transmissive operating mode or a reflective operatingmode.
 6. The monitoring system according to claim 1, further comprisinga velocity sensor configured to generate a velocity signal representinga velocity of the flow of crop residue.
 7. The monitoring systemaccording to claim 1, wherein the crop parameter comprises a layerthickness of the flow of crop residue.
 8. The monitoring systemaccording to claim 1, wherein the processor is further configured toreceive an operating parameter of the combine harvester and determine avolume of the flow of crop residue based on the operating parameter ofthe harvester and the response signal.
 9. The monitoring systemaccording to claim 1, wherein the processor is further configured toreceive an intake parameter representing a weight per unit of time ofthe crop harvested.
 10. A combine harvester, comprising: a header forharvesting a crop of a field; a threshing system for separating a cropresidue from the harvested crop; a straw hood comprising a ramp forguiding a flow of crop residue towards the field; and a monitoringsystem, comprising: a sensor configured to provide a measurement wave tothe flow of crop residue as the crop residue progresses on the ramp ofthe straw hood and to receive a response wave from the flow of cropresidue as the crop residue progresses on the ramp of the straw hood;and a processor comprising an input terminal for receiving a responsesignal of the sensor representative of the response wave, the processorconfigured to determine a crop parameter associated with a density ofthe flow of crop residue based on the response signal of the sensor, theprocessor further comprising an output terminal for outputting a densitysignal based on the crop parameter.
 11. The combine harvester accordingto claim 10, wherein the response wave originates from at least one of atop surface of the flow of crop residue on the ramp of the straw hoodand a surface of the ramp of the straw hood.
 12. The combine harvesteraccording to claim 10, wherein, during use, the flow of crop residue isarranged between the sensor and the straw hood.
 13. The combineharvester according to claim 10, further comprising a control unit forcontrolling an operating parameter of the threshing system, the controlunit comprising: a second input terminal for receiving the densitysignal; a second processor for processing the density signal anddetermining a control signal for the threshing system based on thedensity signal; and a second output terminal for outputting the controlsignal to the threshing system to control the operating parameter. 14.The combine harvester according to claim 13, wherein the threshingsystem comprises a rotor that is at least partially enclosed by aperforated concave, the operating parameter being a position of theconcave relative to the rotor or a velocity of the rotor.
 15. Thecombine harvester according to claim 10, wherein the sensor is anultrasonic sensor comprising a transmitter configured to transmit themeasurement wave to the flow of crop residue and a receiver configuredto receive the response wave from the flow of crop residue.
 16. Thecombine harvester according to claim 15, wherein the transmitter isconfigured to output an ultrasonic pulse as the measurement wave, thereceiver being configured to receive, as the response wave, a responseof the ultrasonic pulse after impacting the flow of crop residue. 17.The combine harvester according to claim 15, wherein the transmitter andreceiver are configured in a transmissive operating mode or a reflectiveoperating mode.
 18. The combine harvester according to claim 10, whereinthe monitoring system further comprising a velocity sensor configured togenerate a velocity signal representing a velocity of the flow of cropresidue.
 19. The combine harvester according to claim 10, wherein thecrop parameter comprises a layer thickness of the flow of crop residue.20. The combine harvester according to claim 10, wherein the processoris further configured to receive an intake parameter representing aweight per unit of time of the crop harvested.